Power distribution network single-phase earth fault locating method based on transient state

Abstract

The invention relates to a method for detecting faults in cables, transmission lines or networks, in particular to a power distribution network single-phase earth fault locating method based on a transient state. The method includes: first, determining fault section in a large range according to a flow direction of detecting point transient current, and then determining a final fault section according to the similarity of zero-module current waveforms between two adjacent detecting points. The current waveform similarity calculating processing adopts a general correlation coefficient calculating method and a maximum correlation coefficient calculating method respectively. The technical scheme is that the method is a passive route selection method which is high in locating success rate and efficiency and not subject to effects of unstable arc and intermittent arc, an additional high-voltage primary device or movement coordination of other primary devices is not required, and high safety is achieved. Outage is not required for installing and detecting, and required installing space is small.

Description

technical field [0001] The invention relates to a method for detecting faults in cables, transmission lines or networks, in particular to a method for locating single-phase grounding faults in distribution networks based on transient signals. Background technique [0002] Single-phase ground fault is the primary fault form of distribution network, accounting for about 80% of the total faults. If considering the instantaneous ground fault with higher frequency and easy to be ignored, its proportion is even higher. When a fault occurs in the medium-voltage distribution network, it is necessary to determine the fault line (fault line selection), determine the fault location (fault location), and automatically isolate the fault section (adaptive tripping). The purpose is to remove the fault, avoid power outages or reduce The number of power outages and the time of power outages can improve the reliability of power supply. [0003] Distribution network fault location is divided ...

AI Technical Summary

Problems solved by technology

However, the application report of active positioning technology in DOA system has not been seen yet, and its application is mainly concentrated in fault indicators. The success rate of positioning depends on the amplitude of the additional current signal and its characteristic difference with the power frequency. Stable arcs and intermittent arcs are seriously affected, and instantaneous ground faults cannot be detected; additional high-voltage primary equipment is required, or other primary equipment actions are required to cooperate, which poses a greater safety hazard to the system

If the input resistance cannot be removed in time due to faults and other reasons, it will be burned

The fault current at the fault point is increased, up to tens of amperes. Although the time for increasing the current is short, it also deviates from the original intention of reducing the fault current to facilitate automatic arc extinguishing, and increases the damage of the fault point, especially For more serious faults such as two-phase short circuit caused by cable fault, it also has a certain degree of impact on the primary system; in addition, the method of adjusting or adding primary equipment must be installed in a power failure, and the installation space required in the substation is large

Images